Exam 10 Mar 24 Need to have the electrical message jump from the bottom th Monday Electrocardiogram EKG figure 12 11 o P wave atrial depolarization contraction top down push the blood down atrial contraction o QRS complex ventricular depolarization the Lub is due to the shutting of AV valves appears at the beginning of the systolic period When ventricles contract obscure atrial repolarization o T wave ventricular repolarization the contraction of atria the Dub Sounds o Lubs post QRS Cuspids closing squeezing the ventricle what s the sound At the left ventricle go up to the aorta slam the door making the sound o Dubs post T don t want the blood to go back semilunar closing o Murmur lub sh dub sh lub sh dub lub dub sh failure to completely close having back flow Problematic Cardiac cycle Blood pressure contraction of space PV nRT decrease the volume inside of the heart fluids n amount of blood constant here T temperature constant here R constant PV C P and V inverse relationship Two phases fill then empty o Systole contract for ejecting 1 3 of the time squeezing phase o Diastole relax for filling 2 3 of the time Stroke volume SV EDV ESV o End diastolic V EDV pre contract biggest amount of blood in the heart when the 4 chambers of the heart are all relaxing max V 135 mL o End systolic V ESV post contract of the ventricle contraction strongest squeeze still leaves volume in the heart min 65 mL Not easy to measure the blood volume change in the aorta just measure the volume in the heart Heart rate HR cycles min Cardiac out put CO SV x HR o Typical 70 mL beats x 70 beats min 4 9 L min Regulation of CO CO SV x HR EDV ESV x HR Changes o Delta HR o Delta SV delta EDV or delta ESV Relatively independent can change the heart rate without changing the stroke volume and vice versa the rate is not affected by the blood outside and the volume is just determined by the difference between EDV and ESV SV is the volume of blood pumped SV volume in EDV volume out ESV Horizontal is blood pressure decrease as the distance from heart increase the upright pressure is the hydrostatic pressure has inverse relationship with surface area Regulation of HR by the pacemaker cells Autonomic o Sympathetic 1 By increase the input of signal to SA node 2 By increased conduction velocity decrease the time took by your heart to squeeze of the signals passed between cardiac cells finish the cycle more quickly o Parasympathetic exact opposite Others Epi fight and flight need more O2 body T get hot to change the heart rate to cool you down and got cold to change to warm up Electrolytes ions Ca Na and K Endocrines eg testosterone do not use if have a hear disease Regulation of SV 1 Increase EDV fill up the heart a little bit more force when stretched a little By increasing the force can contract the ventricle decrease the ESV volume get more blood out Increase potential for cross bridges when you have increased EDV want to increase the muscle contraction to get the blood out If too much stretch broken take away the contraction decrease the force congestive heart failure stretch too far Treat the heart let it relax so that the heart can heal itself not so much these days 2 Delta arterial P ventricle ejects to aorta artery Pumping against P gradient resistance 3 Sympathetic NE and Epi will increase contractility at any V Epinephrine is always secreted from kidneys transported through the blood diffuse through the blood vessels to the surrounding smooth muscles Epi has different effects on different parts of blood vessels dilate the smooth muscles surrounding vessels sending blood to the skeletal muscles but contract the smooth muscles surrounding vessels sending blood to non skeletal muscle areas SNS input increase strength of ventricular contraction regardless of EDV March 26th Blood vessels figure 12 30 All types are lined with endothelium have tight junctions Arteries away from heart not always oxygenated blood like pulmonary artery o Highly elastic lowering variation only 1 3 sending blood but we don t want the body get blood at 1 3 time but not get in 2 3 of the time so when we send the blood out some of the blood push the vessels across the diameter of not the elasticity the vessels will break and the blood will flow out So the variation goes lower and have continuous blood sending o Smooth muscle o Highest hydrostatic Pressure not the same thing as the blood pressure based on fluid water when the blood is pushing the wall there is also hydrostatic pressure The perpendicular pressure is the hydrostatic pressure and the horizontal pressure is the BP Eg Wants to wear snow shoes in snowing days to dissipate the pressure right near the heart so the blood pressure is high the amount of wall is very little very high hydrostatic pressure breakings having at arteries because of this pressure like aneurism Arterioles smaller o Less elastic o Smooth muscle o High hydrostatic pressure but not the highest less than in arteries because increased surface area and also minor away from the heart Capillaries smallest RBC the RBCs are just squeezing the capillaries diameter cannot be smaller figure 12 40 12 39 o Very thin walls only 1 cell o Site exchange Diffusion epithelial cell we live on diffusion so we need these walls be thin Increased surface area is huge The hydrostatic area is large Decreased flow rate want to get diffusion so we want the speed low eg Go to a restaurant eating buffet on a o Lowest hydrostatic pressure Venules returning naming according to direction towards the heart o Thin walled eg buildings in Chicago need to be built stronger but not in Columbus because that will be a waste of money o Low hydrostatic pressure Endothelium made up the capillary vessels and secrete endocrines paracrine and autocrine Veins bigger returning o Lowering hydrostatic pressure higher than in the venules o Smooth muscle change the amount of blood goes back to the heart by the controls of the veins problem against the gravity Force the heart is pushing keep pushing it so cannot go back o Flow still based on heart But aided by One way valves only allowed to flow to the heart Skeletal muscle helping but not circulating Blood pressure Arterial BP o Determined by 1 V of blood 2 Wall s rigidity PV nRT V is the space o In large vessels mirror cardiac cycle Systolic P max contraction end Top number on the BP report sheet Diastolic P min before contraction Bottom number on the Arteriolar BP the most important report sheet o Arterioles
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